The invention relates to a pick-up head and/or cutter for scanning or cutting information in a track of a rotating information-carrier disc; and more particularly to a pick-up or cutter for stereo phonograph recordings in which the information comprises signals in two orthogonal directions of oscillation. As used hereinafter the term "pick-up" should be understood to refer both to pick-up and cutting heads.
The pick-up head comprises a stylus unit with a stylus support carrying a stylus on one end, and a magnet system which directs magnetic fields and cooperates with the stylus unit. The magnetic system comprises two coils and pole pieces which each correspond to one of the two orthogonal directions of oscillation, and a third pole piece which is common to the two directions of oscillation.
Such a pick-up head is disclosed in German Auslegeschrift No. 25 12 467 to which U.S. Pat. No. 4,031,335 corresponds. The magnet system comprises two pole rods on which cylindrical coils are arranged. The ends of the pole rods which are situated within the magnetic field are U-shaped and form the two first-mentioned pole pieces. They are arranged adjacent each other opposite the third pole piece, which is formed by the screening shell. The stylus is located in the magnetic field between the two pole pieces and the third pole piece, and is mounted in an elastic suspension block. A permanent or soft-magnetic transducer element is arranged on the stylus.
In comparison with known transducers this construction is simpler owing to the use of a common third pole piece, but its weight remains comparatively high and its assembly remains comparatively intricate.